New plane and spherical trigonometry, surveying, and navigation (1903)
Wentworth, G. A. (George Albert), 1835-1906 · Boston : Ginn & Company · leaf 97
c2 - 2 be cos A. 1. When A = 90°, cosA = 0..-. a2 = b2 4- c2. 2. When A = 0°, cos A = 1..-. a2 = 62 + c2 - 2 6c. 3. When A = 180°, cos A = - 1..-. a2 = 62 + c2 + 2 6c. 4. A right triangle. 5. A straight line. A ? C 6 =AC.6. A straight line.A c = AB. a = b — c. B a = BC.b =AC. c = BA.a = b + c. 4.… … A C £ D Fig. 2. Case I. When angle B is acute (Fig. 1). cos 5 == a AD cos A = .-. DB = a cos B,and AD = 6 cos A. .-. DB+AD = acos 2?+6 cos A.But DB-\-AD = c. .-. c = a cos 2? + 6 cos A. Case II. When angle 5 is obtuse(Fig. 2). AD 6 BD a = — cos B..\ AD = b cos A,and jBD = — a cos J5. cos A.= cos…
Trigonometry · Surveying · Navigation
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
